std::feraiseexcept

 

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通用的数值运算 Original: Generic numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

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浮点环境

功能 Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

feclearexcept （C++11）

fetestexcept （C++11）

feraiseexcept （C++11）

fegetexceptflag fesetexceptflag （C++11） （C++11）

fegetround fesetround （C++11） （C++11）

fegetenv fesetenv （C++11）

feholdexcept （C++11）

feupdateenv （C++11）

宏常量 Original: Macro constants The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

FE_ALL_EXCEPT FE_DIVBYZERO FE_INEXACT FE_INVALID FE_OVERFLOW FE_UNDERFLOW （C++11）

FE_DOWNWARD FE_TONEAREST FE_TOWARDZERO FE_UPWARD （C++11）

FE_DFL_ENV （C++11）

 

Defined in header <cfenv>
int feraiseexcept( int excepts );		（C++11 起）

试图提高中列出excepts的浮点异常（OR运算的浮点例外宏）。如果是一个例外是FE_OVERFLOW或FE_UNDERFLOW，此功能可额外提高FE_INEXACT。会引发异常的顺序是不确定的，除了FE_OVERFLOW和FE_UNDERFLOW前提出FE_INEXACT.

Original:

Attempts to raise all floating point exceptions listed in excepts (a bitwise OR of the 浮点例外宏). If one of the exceptions is FE_OVERFLOW or FE_UNDERFLOW, this function may additionally raise FE_INEXACT. The order in which the exceptions are raised is unspecified, except that FE_OVERFLOW and FE_UNDERFLOW are always raised before FE_INEXACT.

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参数

excepts

-

列出的异常标志的位掩码提高 Original: bitmask listing the exception flags to raise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

返回值

​0​如果所有上市的例外情况，提出了非零值，否则.....

Original:

​0​ if all listed exceptions were raised, non-zero value otherwise.

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为例

#include <iostream>
#include <cfenv>
 
#pragma STDC FENV_ACCESS ON
 
int main()
{
    std::feclearexcept(FE_ALL_EXCEPT);
    int r = std::feraiseexcept(FE_UNDERFLOW | FE_DIVBYZERO);
    std::cout <<  "Raising divbyzero and underflow simultaneously "
              << (r?"fails":"succeeds") << " and results in\n";
    int e = std::fetestexcept(FE_ALL_EXCEPT);
    if (e & FE_DIVBYZERO) {
        std::cout << "division by zero\n";
    }
    if (e & FE_INEXACT) {
        std::cout << "inexact\n";
    }
    if (e & FE_INVALID) {
        std::cout << "invalid\n";
    }
    if (e & FE_UNDERFLOW) {
        std::cout << "underflow\n";
    }
    if (e & FE_OVERFLOW) {
        std::cout << "overflow\n";
    }
}

Output:

Raising divbyzero and underflow simultaneously succeeds and results in
division by zero
underflow

另请参阅

feclearexcept （C++11）	清除指定的浮点状态标志 Original: clears the specified floating-point status flags The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数）
fetestexcept （C++11）	确定哪些指定浮点状态标志被设置 Original: determines which of the specified floating-point status flags are set The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数）